1. Field of the Invention
The present invention relates to a silicon wafer suited for use in a semiconductor device manufacturing process which conducts heat treatment at a maximum temperature of 1100° C. or more and at a rate of temperature increase of 300° C./sec or more after the silicon wafer which is the base material of the device has undergone a mirror machining process, and to a manufacturing method thereof.
Priority is claimed on Japanese Patent Application No. 2007-036630, filed Feb. 16, 2007, the content of which is incorporated herein by reference.
2. Description of Related Art
Due to the ever higher integration of devices, furnaces exhibiting rapid temperature increases and decreases have come into frequent use in device manufacturing processes (see Patent Reference 1), and their maximum temperatures are also trending upward. In particular, in the case of unilateral heating inside furnaces exhibiting rapid temperature increases and decreases, it happens—although for a very short time—that a large temperature disparity occurs between the front face and rear face of the wafer.
When a large temperature disparity occurs between the front and rear faces in this manner even for a short time, it has been found that slip dislocations may occur from the oxygen precipitate existing in the vicinity of surface layer of the wafer, which may move to the surface layer of the wafer (the active layer side of the device), and penetrate the surface.
Moreover, when punch-out dislocations which arise from oxygen precipitate before heat treatment involving rapid temperature increase/decrease and when dislocation clusters which are aggregates of interstitial silicon exist in the wafer, high stress is sustained, slip dislocations occur, and the surface layer of the wafer is penetrated. When such dislocations exist in the active layer of the device, they cause leak defects in the device, and degrade device yield.
Patent Reference 1: Japanese Unexamined Patent Application, First Publication No. 2006-310690